1. Field of Invention
Aspects of the invention can relate to a projector for projecting an image using a liquid crystal display panel, and other display units.
2. Description of Related Art
In related art projectors having a display element composed of discrete pixels, there are some projectors which incorporate an optical unit configured such that a plurality of wobbling elements each having a switch type phase modulation optical element which are optically transparent, and composed of a ferroelectric liquid crystal, and the like, and an optically transparent birefringent medium are stacked one on another. See, for example, JP-A-7-36054.
With such a projector, the operation of the phase modulation optical element can be switched during one frame, thereby to alternately switch the polarization direction of the light passing through the birefringent optical element to the orthogonal direction. As a result, the optical path of the light emitted through the phase modulation optical element and the birefringent medium is switched during one frame. This allows the gap between pixels to be filled in. As a result, it is possible to project the image of the display element composed of discrete pixels as a seamless continuous image.
However, with the foregoing related art projector, the phase modulation optical element is switched during one frame period to be driven. Therefore, it is not easy to ensure the stable operation of the phase modulation optical element. As a result, the phase modulation optical element or the driving circuit itself can become costly, or the resulting image tends to be instable.
Further, with the foregoing related art projector, the transmittance reduction to a certain degree or more cannot be avoided, nor the occurrence of the nonuniform transmittance cannot be avoided, either. Accordingly, the reduction of luminance and the nonuniform luminance of the projected image inevitably occur.